The Lutheran World Federation has invited the pope to work together in preparing for the 500th anniversary of the Protestant Reformation.

In a message Thursday to Pope Benedict XVI, LWF President Bishop Dr. Munib A. Younan said the anniversary in 2017 will not only be a time of celebrating the liberating power of the Gospel but also a time to reflect on ecumenical progress.

He called the anniversary a "test case" for ecumenical relations.

"[W]e intend our anniversary to be ecumenically accountable: to recognize both damaging aspects of the Reformation and ecumenical progress since the last major Reformation anniversary," Younan said. "But we cannot achieve this ecumenical accountability on our own, without your help.

"We are called, both Lutherans and Catholics, to our common vocation of witnessing to the world for the sake of Christ’s kingdom."

Younan led a seven-member delegation in a private audience with the pope.

As they approach the Reformation anniversary in a few years, Pope Benedict said "Catholics and Lutherans are called to reflect anew on where our journey towards unity has led us and to implore the Lord's guidance and help for the future."

Leaders from the LWF and the Roman Catholic Church have been in dialogue for decades. Some of the key issues discussed between the two global church bodies include the Eucharist, unity and justification.

Ecumenical relations between the two bodies reached a historic point when they signed the Joint Declaration on the Doctrine of Justification in 1999. The doctrine of justification had divided Protestants and Catholics for hundreds of years, as those from the Lutheran tradition broke from the Roman Catholic Church and gave rise to the Protestant Reformation.

"From the Reformation perspective, justification was the crux of all the disputes," the joint declaration states.

Justification deals with salvation and the forgiveness of sins. Part of the declaration reads, "We ... share the conviction that the message of justification directs us in a special way towards the heart of the New Testament witness to God’s saving action in Christ: it tells us that as sinners our new life is solely due to the forgiving and renewing mercy that God imparts as a gift and we receive in faith, and never can merit in any way."

Stressing the progress Lutherans and Catholics have made, Younan expressed joy over the new levels of theological understanding and agreement and noted that "the climate of relations" between the two "has warmed dramatically."

The LWF president reaffirmed to the pope the Lutheran body's commitment to their ecumenical relationship.

He also expressed solidarity with the Roman Catholic Church in supporting a two-state solution to the Israel-Palestine conflict.

Looking to more progress, Younan said, "While we rejoice in each small step which brings us closer together, we do not want to be content with these steps."

Younan was elected president of LWF in July. He was joined in his visit with the pope by leaders representing every LWF region. LWF has 145 member churches in 79 countries, representing over 70 million Christians.